The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the electronics industry utilized various techniques to implement distributed systems including multi-phase power systems and particularly power systems that used multiple power supply controllers to control the value of an output voltage. Typically, such multiple power supply controllers each utilized a separate oscillator for controlling each power supply. The power supply systems typically connected the power supply controllers together and synchronized all the oscillators to a frequency of the oscillator of one of the power supply controllers.
One problem with such power supply controllers and power supply systems was the cost of implementing the systems. Typically, the power supply controllers required more than one signal input to control the synchronization of the frequencies of the internal oscillators. Integrating one of these controllers into a single semiconductor die resulted in the synchronization signals requiring more than one pin of the semiconductor package. This caused the controller to use a package that had more pins than was desired thereby increasing the cost of the controller.
Some of the prior controllers required an output pin to drive multiple capacitors in order to perform the synchronization. This caused the circuits to drive large capacitive loads which resulted in more power dissipation and delays in performing the synchronization.
Accordingly, it is desirable to have a power supply controller that can synchronize to externally received frequencies, that does not have jitter in the oscillator frequency, that uses only one package pin for the synchronizing signals, and that has a lower cost.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, or certain N-type or P-type doped regions, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein relating to circuit operation are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. The use of the word approximately or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to at least ten percent (10%) are reasonable variances from the ideal goal of exactly as described.